One component diazotype material containing at least two light sensitive diazocompounds



United States Patent ONE CONIPONENT DIAZOTYPE MATERIAL CON TAINING AT LEAST TWO LIGHT SENSITIVE DIAZOCOMPOUNDS Theodorus Petrus Wilhelmus Sanders and Karel Maria Hutgens, Venlo, Netherlands, assignors tr; Cllimlstilt- Fabriek L. van der Grinten N. V., Venlo, Netherlands, a limited liability company of the Netherlands Application July 29, 1953, Serial No. 371,022 Claims priority, application Netherlands August 13, 1952 6 Claims. (Cl. 96-91) The invention relates to one component positive diazotype material, the light sensitive layer of which contains at least two light sensitive diazo compounds, of two distinct types. The diazotype material according to the invention is particularly valuable for copying from what are often called artistic tracings, for example of furniture or architectural subjects, drawn in lead-pencil and crayon. There is a demand for diazotype material yielding pictures giving a good rendering of the lead-pencil and crayon lines of the said artistic tracings. The materials may also be usefully applied to copying from continuous tone diapositives if the light sensitive layer is a diazo film layer. The diiferent types of diazo compounds will hereinafter be described.

The semi-wet diazotype process has become of considerable importance for the development of one component diazotype material. Diazotype materials suitable for the said development and yielding good prints after development with a thin film of for instance 9 g. per n1. of an aqueous developing solution containing one or more azocoupling components, such as resorcinol and phloroglucinol, and suitable butter salts (this being the kind of developer almost universally used for semi-wet diazotype development) already exist.

For these one component diazotype materials diazo compounds of the following structure are preferred:

wherein R1 and R2 each represent an alkyl radical, X is an anion and Y a substituent. Diazo compounds of this kind are preferred for various technical reasons, for example because the amino compounds from which they are prepared are stable and because these diazo com pounds have sufiicient coupling activity for development with buttered developing solutions of a slightly alkaline reaction. Any substituent Y in the position indicated makes this type of diazo compound, as far as the coupling activity is concerned, suitable for semi-wet development as previously defined, even substituents such as SOsH and COOH are suitable, though, in general, the latter have a tendency to decrease rather than to increase the coupling activity. (Of course, the azodyestuffs formed should not be too soluble as they would then have a tendency to bleed.)

Diazotypc materials containing these diazo compounds do not however yield good renderings of the said artistic tracings, the gradation produced being too steep if the diazo content is higher than 0.3 millimol per square metre, and if-as is normalthe decomposition product formed Patented May 21, 1957 from the diazo compound upon exposure does not yield an internal screen, which internal screen would prolong exposure. The diazo content of normal diazotype materials is usually higher than 0.3 millimol per square meter, in order to obtain copies of sufiicient density of line.

It is an object of this invention to provide diazotype materials for the semi-wet development process which yield sufficiently strong copies, need approximately normal exposures, have less steep gradation and thus yield better rendition of tracings in lead-pencil and crayon and of continuous tone diapositives than do the known diazotype materials containing the above-mentioned diazo compounds.

Sunlight may be used for the purpose of diazotype printing, but nowadays a mercury vapour lamp (usually a high pressure mercury vapour lamp) is most frequently used. The diazotype material according to the invention will produce better rendition of the said artistic tracings when the exposure is made in sunlight or when made in the light of a mercury vapour lamp. If not otherwise stated the use of a high pressure mercury vapour lamp will, in the following description, be supposed. When exposed in monochromatic light, the required effect is not produced. Likewise when the material is exposed to carbon arc-light, which formerly was frequently used, and still is used, for diazotype printing, there will be no appreciable effect.

One component diazotype material, provided according to this invention, contains at least two different types (type i and ll) of light sensitive diazo compounds and has a total content of at least 0.3 millimol diazo compound per m9. The novelty of this material consists in the following: it contains at least one diazo compound of type 1 of the following structure:

wherein R1 and R2 each represent an alkyl radical, X is an anion and Y a substituent, which has, for rays of 4050 A., an epsilon value greater than 1.5)(10 and, for rays of 3650 A., an epsilon value lower than that for rays of 4050 A.; it contains at least one diazo compound of type II having, for rays of 3650 A., an epsilon value greater than 1.5 10 and, for rays of 4050 A., an epsilon value lower than for rays of 3650 A.; for rays of 4050 A. the epsilon value of the diazo compound(s) of type 1 minus the epsilon value of the diazo compound(s) of type II is at least LOXIO; for rays of 3650 A. the epsilon value of the diazo compound(s) of type II minus the epsilon value of the diazo compound(s) of type I is at least l.0 l0 the gamma value of the diazotype material containing the mixture of the diazo compounds of types I and II is less than that of material with the diazo compound(s) of type I or type ll, (whichever of these types has the lower gamma value), and the diazo compounds couple more rapidly than p-diazodiethylaniline.

By total content of diazo compounds is to be understood the content of all the diazo compounds present in the diazotype material, i. e. the one or more diazo compounds of type I plus the one or more diazo compounds of type II, plus possibly other diazo compounds present in the diazo layer.

The term epsilon indicates the molar extinction coeificient, as measured in a layer of one centimetre thickness of an aqueous molar solution of the diazo compound.

A. stands for Angstrom units.

If the quantities of the diazo compounds of type I and type II are chosen in a suitable ratio, then the diazotype material according to the invention will yield a picture of softer gradation than a diazotype material with the same total" diazo content but made with only the softest working of these diazo compounds. This is schematically illustrated by the graph of the drawing. The ordinate of the graph indicates gamma values as derived from Example 1. As will be later described in said example the points 1, 2, 3, 4 and 5 in the graph have been calculated from the series of gamma value determinations, carried out on stepwedge prints on five diazotype materials coated with the same diazo compounds of both the types I and II, but in varying ratios.

Point 1 indicates the gamma value, when only the diazo compound of type I has been used, point 5 the gamma value of the corresponding diazotype material, exclusively coated with the diazo compound of type II. The points 2, 3 and 4 indicate the gamma values obtained with diazotype materials containing both the diazo compounds in three difierent ratios.

As the experiments of Example 1 demonstrate, each ratio has a corresponding gamma value. By varying the ratio between the amounts of the diazo compounds of the types I and II, the desired gamma value, for example the lowest of the gamma values for these mixtures, can be obtained. In the figure it can be seen that the lowest gamma value is to be found very near to point 3. This lowest gamma value is not, however, always the most desirable. Which of the possible gamma values will give the most attractive results may depend on the nature of the tracing or diapositive to be reproduced. At all events, however, the gamma value of the diazotype material containing the mixture of the diazo compounds of types I and II should be less than the gamma values of comparable diazotype materials respectively containing only one of the diazo compounds of said mixture, of either type I or II. So the mixture 4 does not enter into the scope of this invention, as its gamma value is the same as that of a material containing diazo compound l. The rapidity of coupling in comparison with that of p-diazodiethylaniline can be determined in vitro by measuring the time in which a certain portion (e. g. of the diazo compound to be measured will have coupled in a given molar concentration (e. g. 0.1 millimolar), with the coupling component phenylmethylpyrazolone in a given molar concentration (e. g. 1.0 millimolar) in a butter mixture of a given composition and having a given pH value, at a given temperature.

A two-component diazotype material containing two diazo compounds, viz.: l-diazo-4-dimethylamino-2-carboxybenzene and l-diazo4-m0noethylamino-3-methylbenzene, and one or more azo-coupling components, which after exposure under the tracing and development in gaseous ammonia, gives a good rendering of lead-pencil and crayon lines, is known. This diazotype material does not contain a mixture of diazo compounds used according to the invention and it is not suitable for the semi-wet development diazotype process, because the diazo compounds have insufficient coupling activity for this process.

It was found that if, as the diazo compounds of type 11, compounds of the following structure are chosen:

wherein R represents a cyclohexyl radical. Of particular importance are combinations of diazo compounds of the following structures:

In both the formulae X represents an anion, while R is a cyclohexyl radical. These two diazo compounds form a particularly effective combination for obtaining good rendition of artistic tracings and at the same time are readily available. In the above formulae the cyclohexyl radical may with advantage be cyclohexyl itself or cyclohexyl substituted by one or more methyl groups.

Some examples of suitable diazo compounds of type I are: 1-diazo-4-diethylamino-3-methylbenzene, l-diazo-4- N-methyl N-cyclohexyl amino-3-chlorobenzene, l-diazo- 4-diethylamino-3-chlorobenzene; some of type II are: ldiazo-4-cthylbenzylaminobenzene, l-diazo-4-monoethylamino-3-trifiuoromethylbcnzene, 1 diazo- 4 -monocyclohexyl-amino-3-chlorobenzene, l-diazo-4-mono(4'methylcyclohexyl) amino-B-chlorobenzene.

The invention is not limited to diazotype material, containing only one diazo compound of type I' plus one diazo compound of type II. As will appear from the examples, more than one of either of the two types may be used. Likewise it may be advantageous, for example for obtaining a special hue in the copies, to add to the diazo mixture one or more diazo compounds not belonging to either of the types I or II in small quantities which will not essentially interfere with the etfect which should be obtained according to the invention. Examples of such diazo compounds are: l-diazo-ZzS-diethoxy- 4 benzoylaminobenzene, l-diazo-Z:S-dibenzyloxyi-benzoylaminobenzene, l-diazo-2z5-dibutoxy-4 acetylaminobenzene, 1-diazo-2 5-diethoxy-4-ethylmercaptobenzene, ldiazo 2:5-diethoxy-4-(4-ethoxyphenyl)benzene, l-diazo- Z-diethylaminobenzene, l-diazo-4-phenylaminobenzene, 1- diazo-4- (4'-ethoxy-phenylamino -benzene.

The diazotype material according to the invention may as also illustrated in the examples, contain additional chemicals, such as are in general use in diazotype materials.

The diazo compoimds used, should, of course, bleach out upon exposure, so as to yield a colourless or nearly colourless background.

The sensitizing preparations may be applied to the base or support in any of various ways well known to those skilled in the art, for example, by dipping, spraying, coating, or brushing. They may be applied in excess, the excess being subsequently removed, for example, by a doctor blade or roller or an air jet.

The following examples illustrate the invention:

Example 1 In this example two diazo compounds, the one of type I and the other of type II, are used. For rays of 3650 A. diazo compound type I has an epsilon value of approximately l.5 and diazo compound type II one of approximately 3.5 1O For rays of 4050 A. diazo compound type I has an epsilon value of approximately 3.1)(10 and diazo compound type II one of approximately 0.2 10 Both the diazo compounds yield a clear background upon exposure to light.

A sheet of strawpulp paper of 80 g. per m3, suitable for the diazotype process, was prepared with a solution, which contained:

0.11 mol zinc chloride double salt of l-diazo-4-dielhylamino-3-chlorobenzene(diazo compound type I) 20 g. sodium salt of naphthalene-l:3:6trisulphonic acid g. ammonium sulphate 10 cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

The treatment was so carried out, that the paper surface contained 0.90 millimol of the diazo compound per 111. (diazotype paper No. 1).

A second sheet of the same strawpulp paper was prepared with a solution containing:

0.11 mol zinc chloride double salt of l-diazo-4-monocy clohexylamino-3-chlorobenzene(diazo compound type II) g. sodium salt of naphthalene-1:3:6-trisulphonic acid 15 g. ammonium sulphate 10 cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

This paper surface also contained 0.90 millimol of the diazo compound per :11. (diazotype paper No. 5).

Sheets of the same strawpulp paper were prepared with mixtures of the two above solutions so that three further diazotype papers (Nos. 2, 3 and 4) were obtained, respectively having at their surfaces:

0.68 millimol per m? diazo compound of type I plus 0.22

millimol per m. diazo compound of type II;

0.45 millimol per m? diazo compound of type I plus 0.45

millimol per m? diazo compound of type II;

0.22 millimol per m. diazo compound of type I plus 0.68

millimol per m? diazo compound of type II.

The five diazotype papers were exposed under a neutral stepwedge, after which they were developed by the ap plication of approximately 9 g. per 111. of the following developing solution:

43 g. potassium tetraborate pentahydrate 10 g. potassium hydroxide (85%) 32 g. thiourea 6.5 g. phloroglucinol 6.5 g. resorcinol 1 g. potassium salt of hydroquinone monosulphonic acid 20 g. sorbitol 2.5 g. sodium salt of isoproplynaphthalene sulphonic acid 1000 cc. water.

In each of the copies of the stepwedge thus obtained, the reflexion densities of the steps were measured in mono- 6 chromatic light of 5460 A. The characteristic curve of each of the stepwedge copies was plotted and the gamma value thereof was determined. The same series of five experiments was repeated three times, each time exposing five freshly sensitized sheets. The results obtained are listed in the following table:

Diazo Dingo Diazotype comp. comp. Gamma value of Average paper No. typo I in type II in characteristic gamma millimol millimol curve value per ml per m.'-

m r I l 0.9 0.0 2.4 2.2 2.3 2.3 2. 0.08 0.22 2.1 2.1 2.1 2.1 3 l). 45 0. 45 2.0 1.8 1.9 1.9 4 0.22 0. 68 2.2 2.3 2. 4 2. 3 5 r 0.0 0.0 2.4 2. 3 2. 5 2.4

Example 2 A sheet of paper of g. per mi, suitable for the diazotype process, was coated with a solution, which contained:

0.05 mol zinc chlorine double salt of 1-diazo-4-(N- methyl-N-cyclohexyl)amino-3-chlorobenzene (type I; epsilon at 3650 A.=1.l l0 at 4050 A.=3.2 l0

0.02 mol zinc chloride double salt of l-diazo-4-monoethylamino-3-trifiuoromethylbenzene (type II; epsilon at 3650 A.=2.6 10 at 4050 A.=0.037 l0 5 g. tartaric acid,

10 cc. of an aqueous solution of 4% by weight of methylcellulose in 1 litre of water and dried.

The paper surface contained: approximately 0.5 millimol diazo compound of type I and approximately 0.2 millimol diazo compound of type II per m).

The sheet was exposed (with slight under-exposure) under a tracing, drawn in lead-pencil and crayon on natural tracing paper, and developed by the application of a film of approximately 9 g. per m? of the following developing liquid:

40 g. tertiary sodium phosphate (NasPO4.l2H2O),

30 g. sodium salt of beta-naphthol,

20 g. thiourea,

2.5 g. sodium salt of isopropylnaphthalene sulphonic acid, 1000 cc. Water.

A brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances with a diazotype paper containing, in a concentration equal to the total diazo content of the example, the softer working diazo compound only. 1- diazo-4- N-methyl-N-cyclohexyl amino-3 chlorobenzene was prepared in the same way as the diazo compounds of Example 1, using N-methyl N-cyclohexylamine in this case. 1 diazo-4-monoethylamino-3-trifluoromethylbenzene was prepared by condensation of 1-nitro-3-trifiuoromethyl-4-chlorobenzene with monoethylamine and reduction and diazotization as described for the diazo compounds of Example 1.

Example 3 A sheet of woodpulp paper of 80 g. per in suitable for the diazotype process, was coated with a solution, which contained:

in 1 litre of water and dried.

The application was made so that the treated paper surface contained: approximately 0.48 millimol diazo com pound of type I and approximately 0.17 millimol diazo compound of type II, all per mfi.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per in. of the following developing liquid:

35 g. potassium carbonate,

32 g. thiourea,

6.5 g. phloroglucinol,

6.5 g. resorcinol,

2.5 g. sodium salt of isopropylnaphthalene sulphonic acid,

1000 cc. water.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds. 1-diazo-4-diethylamino-3-iodobenzenc was prepared by condensing 1:3-dinitro-4-chlorobenzene with diethylamine followed by partial reduction by means of sodium disulphide, recrystallisation of the 1-nitro-3-amino-4-diethylaminobenzene obtained thereby, diazotization of the amino compound and replacement of the diazo group by the iodo substituent according to the Sandmeyer-reaction, reduction of the 1-nitro-3-iodo-4-diethylaminobenzene and diazotization of the amino compound. l-diazo-4- monoethylamin-3-chlorobenzene was obtained by the method used for making the diazo compounds of Example using monoethylamine.

Example 4 A sheet of paper of 80 g. per m. suitable for the diazotype process, was coated with a solution, which contained:

0.05 mol zinc chloride double salt of l-diazo-4-diethylamino-3-benzoylamino benzene (type I; epsilon at 3650 A.=2.l l0 at 4050 A.=2.4 10

0.02 mol zinc chloride double salt of 1-diazo-4-monocyclohexylamino-3-chlorobenzene (type II; epsilon at 3650 A.==3.9 10 at 4050 A.=0.2 10

8 g. tartaric acid,

10 cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

The application was made so that the treated paper surface contained: approximately 0.5 millimol diazo compound of type I and approximately 0.2 millimol diazo compound of type II per [11.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m of the following developing liquid:

25 g. sodium carbonate (anhydrous),

32 g. thiourea,

14 g. sodium thiosulphate (NazSzO3.5I-IzO),

18 g. monobeta-hydroxyethylamide of 2-hydroxy3-naphthoic acid,

(ill

2.5 g. sodium salt of isopropylnaphthalene sulphonic acid, 1000 cc. water.

A blueish copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working diazo compound. 1-diazo- 4-diethylarnino-3-benzoylaminobenzene was prepared by condensing l-nitro-3-benzoylamino-4-chlorobenzene with dicthylamine, followed by reduction and diazotization.

Example 5 A sheet of g. per mfl, suitable for the diazotype process, was coated with a solution, which contained:

0.05 mol zinc chloride double salt of l-diazo-4 -diethylamino-3-methylbenzene (type I; epsilon at 3650 A: 1.1 10 at 4050 A.=2.4 1O

0.02 mol zinc chloride double salt of l-diazo-4-mono- (4'-methylcyclohexyl)amino-3-chlorobenzene (type II; epsilon at 3650 A.=3.9 l0 at 4050 A.:=0.3 10

10 g. tatraric acid,

10 cc. of an aqueous solution of 4% by weight of methylcellulose in 1 litre of water and dried.

The application was made by applying about 8.5 cc. of the solution per square meter of the sheet material, so as to produce a paper surface containing: approximately 0.43 millimol diazo compound of type I and approximately 0.17 millimol diazo compound of type II per m3.

The sheet was exposed with slight under-exposure in the light of a normal pressure mercury vapour lamp (Cooper Hewitt-lamp) under a tracing, drawn in leadpencil and crayon on natural tracing paper, and developed by the application of a film of approximately 9 g. per mi of the developing liquid described in Example 2.

A brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds. 1diazo-4-diethylamino-3 methylbenzene was obtained by condensing l-nitro3-methyl-4-bromobenzene with diethylamine, reduction and diazotization. l-diazo-4-mono-(4' methylcyclohexyl)amino-3-chlorobenzene was obtained in the same manner as the diazo compound of Example 1, using 4'-methylcyclohexylamine.

Example 6 On a film of g. per in. of cclluloseacctatc with 50% combined acetic acid content there was cast, at a temperature of 30 C., 100 cc. per m? of the following colloidal solution:

30 g. cellulose-acetate with a combined acetic acid content of about 28%,

600 cc. dioxane,

400 cc. water.

The layer thus formed was dried in an air current at 50 C.

Over the original cellulose-acetate film of 50% combined acetic acid there was thus formed a layer of celluloseacetate with 28% combined acetic acid content, of approximately 3 microns thickness. This layer was then impregnated with the following solution:

0.067 mol zinc chloride double salt of l-diazo-4diethylamino-3-methylbenzene (type I; epsilon at 3650 A.:: 1.l l0*; at 4050 A.=2.4 10),

0.033 mol zinc chloride double salt of l-diazo4-monocyclohexylamino-B-chlorobenzene (type II; epsilon at 3650 A.=3.5 10 at 4050 A.=0.2 10

3 g. tartaric acid,

5 g. sodium salt of naphthalene trisulphonic acid-1:3:6,

750 cc. water,

250 cc. ethyl alcohol,

and dried.

The application was made so that the sensitized layer contained: approximately 0.87 millimol diazo compound of type I and approximately 0.43 millimol diazo compound of type II per mi.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per 1n.'- of the developing liquid described in Example 3.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype film containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds. The transparent copy may be used as a diapositive for projection purposes.

Example 7 A sheet of paper of 80 g. per m.'-', suitable for the diazotype process, was coated with a solution, which contained:

0.024 mol zinc chloride double salt of 1-diazo-4-di-n-butylamino-3-chlorobenzene (type I; epsilon at 3650 A: 1.2 l at 4050 A.=3.0 10

0.024 mol zinc chloride double salt of 1-diazo-4(N- methyl-N-cyclohexyl)amino-3-chlorobenzene (type I; epsilon at 3650 A.=1.1 x10 at 4050 A.=3.2 10

0.022 mol zinc chloride double salt of l-diazo-4-monobenzylamino-3-chlorobenzene (type II; epsilon at 3650 A.=3.8 l0 at 4050 A.=O.1 10

5 g. tartaric acid,

cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

The application was made so that the treated paper surface contained: approximately 0.24 millimol of each diazo compound of type I and approximately 0.22 millimol diazo compound of type II per m.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m? of the developing liquid, described in Example 3.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, the diazo compounds of type I only or one of these only or the diazo compound of type II only. The three diazo compounds were manufactured in the same manner as those of Example I using respec tively di-normal-butylamine, N-methyl N-cyclohexyl amine and monobenzylamine.

Example 8 A sheet of paper of 80 g. per m? suitable for the diazotype process, was coated with a solution, which contained:

0.047 mol zinc chloride double salt of 1- diazo 4 diethylamino-3-iodobenzene (type I; epsilon at 3650 A.=1.1 10 at 4050 A.=2.9 10

0.011 mol chlorostannate of l-diazo-4-monocyclohexylamino-3-trifluoromethylbenzene (type II; epsilon at 3650 A.=4.1 X10 at 4050 A.:0.064 l0 0.011 mol zinc chloride double salt of l-diazo-4-mono- 4'-methy1cyclohexyl)amino-3-chlorobenzene (type II; epsilon at 3650 A.=3.9 1O at 4050 A. :0.3) l0 10 g. tartaric acid,

10 cc. of an aqueous solution of 4% by weight of methyl cellulose,

in 1 litre of water and dried.

The application was made so, that the treated paper surface contained: approximately 0.47 millimol diazo compound of type I plus approximately 0.11 millimol of each diazo compound of type 11, per m.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per in. of the following developing liquid:

25 g. sodium carbonate (anhydrous),

32 g. thiourea,

6.5 g. phloroglucinol,

6.5 g. resorcinol,

2.5 g. sodium salt of isopropylnaphthalene sulphonic acid, 1000 cc. water.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, the diazo compound of type I only or the diazo compounds of type II only or one of these only. 1 diazo 4 monocyclohexylamino 3 trifluoromethylbenzene was obtained by condensing l-nitro-Ibtri fiuoromethyl-4-chl0robenzene with monocyclohexylamine, followed by reduction and diazotization.

Example 9 A sheet of paper of 80 g. per m suitable for the diazotype process, was coated with a solution, which contained:

0.042 mol zinc chloride double salt of 1 diazo 4 diethylamino-3-chlorobenzene (type I; epsilon at 3650 A.=1.5 10 at 4050 A.=3.1 10'*),

0.014 mol zinc chloride double salt of 1-diazo-4-monocyclohexylamino-3-chlorobenzene (type Ii; epsilon at 3650 A.=3.5 10 at 4050 A.=0.2 10

0.01 mol l-diazo-4-monophenylaminc-benzene chloride,

10 g. tartaric acid,

10 cc. of an aqueous solution of 4% by weight of methyl cellulose,

in 1 litre of water and dried.

The application was made so that the treated paper surface contained: approximately 0.42 millimol diazo compound of type 1, approximately 0.14 millimol diazo compound of type II and 0.1 millimol l-diazo-4-monophenylamino-benzene chloride per m3.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m. of the developing liquid as described in Example 3.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the diazo compound of type I together with 1-diazo-4-monophenylarnino-benzene chloride or only the diazo compound of type II together with l-diazo4-monophenylamino-benzene chloride. l-diazo- 4-monophenylamino-benzene is commercially available under the name of para-diazo-diphenylamine.

Example 10 Baryta-coated paper was provided on its baryta-coated side with a layer of 10 g. per in? of cellulose acetate with 50% combined acetic acid content. On the cellulose acetate side there was cast, at a temperature of 30 C., cc. per m? of the following colloidal solution:

30 g. cellulose acetate with a combined acetic acid content of approximately 28%,

600 cc. dioxane,

400 cc. water.

The layer thus formed was dried in an air current at 50 C. Over the cellulose acetate layer of 50% combined acetic acid content there was thus formed a layer, approximately 3 microns thick, of cellulose acetate with 28% combined acetic acid content. This latter layer was sensitized by impregnating with the solution of Example 6 and drying.

The application was so made that the sensitized surface contained: approximately 0.87 millimol diazo comwas; i s

11 pound of type I and approximately 0.43 millimol diazo compound of type II per mF.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g, per m? of the developing liquid described in Example 3.

A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds.

Example 11 A sheet of paper of 150 g. per m? was, by means of an adhesive, provided on both sides with a layer, approximately 10 microns thick, of cellulose acetate with 50% combined acetic acid content.

The sheet was superficially hydrolysed on both sides in the following way:

At a temperature of 28 C. the sheet was dipped for half a second in the following solution:

52.5 g. potassium hydroxide, 800 cc. ethyl alcohol, 75 cc. water.

Thereafter the sheet was dried in such a way that it was just dry after 33 seconds. It was then washed in an aqueous solution of 2% oxalic acid for 10 seconds. After this washing operation it was rinsed for 6 seconds at room temperature in running water. Following this second washing the sheet was dried in a period of 24 seconds. One side of the sheet was then impregnated with a solution, which contained:

0.06 mol 1-diazo-4-diisobutylamino 3 sulpho-benzene chloride (type I; epsilon at 3650 A.:l.6 10 at 4050 A.=2.9 10

0.04 mol zinc chloride double salt of l-diazo-4-monocthyl-3-methylbenzene (type II; epsilon at 3650 A. :4.0 l at 4050 A.=0.2X

3 g. tartaric acid in 250 cc. ethyl alcohol and 750 cc. Water and dried.

The application was made so that the sensitized surface contained: approximately 0.22 millimol diazo compound of type I and approximately 0.17 millimol diazo compound of type II per m.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m of the developing liquid described in Example 3. A red brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds. l-diazo-4-diisobutylamino-3-sulpho-benzene was prepared by condensing 1-nitro-3-sulpho-4-chlorobenzene with diisobutylamine, followed by reduction and diazotization.

Example 12 A sheet of paper of 80 g. per m. suitable for the diazotype process, was coated with a solution, which contained:

0.05 mol zinc chloride double salt of l-diazo-4-diethylamino-3-chlorobenzene (type I; epsilon at 3650 A. =l.5 10 at 4050 A.=3.1 10

0.02 mol zinc chloride double salt of l-diazo-4-ethylbenzylaminobenzcne (type II; epsilon at 3650 A. =3.3 10 at 4050 A.=0.9 1O

10 g. tartaric acid,

10 cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

The application was so made, that the treated paper surface contained: approximately 0.38 millimol diazo compound of type I and approximately 0.15 millimol diazo compound of type II per m.

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m? of the developing liquid described in Example 1. A dark, nearly black copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the softer working of the diazo compounds. 1-diazo-4-ethylbenzylaminobenzene was prepared by nitrosation of N-ethyl-N-benzylaniline, reduction and diazotizanon.

Example 13 A sheet of paper of g. per m3, suitable for the diazotypo process, was coated with a solution, which contained:

0.05 mol zinc chloride double salt of 1-diazo-4-diethylamino-3-chlorobenzene (type I; epsilon at 3650 A. =l.5) 10; at 4050 A.=3.l l0

0.02 mol zinc chloride double salt of l-diazo-4-diethylamino-Z-chlorobenzene (type II; epsilon at 3650 A. =3.2 10 at 4050 A.=1.3 10

3 g. tartaric acid,

l0 cc. of an aqueous solution of 4% by weight of methyl cellulose in 1 litre of water and dried.

The application was made so that the treated paper surface contained: approximately 0.40 millimol diazo compound of type I and approximately 0.16 millimol diazo compound of type II per m.".

The sheet was exposed as in Example 2 and developed by the application of a film of approximately 9 g. per m of the developing liquid described in Example 1. A violet brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the exa1n ple, only the softer working of the diazo compounds. 1-diazo-4-diethylamino-2-chlorobenzene was prepared by nitrosation of N-diethyl-m-chloroaniline, reduction and diazotization.

Example 14 A sheet of paper of g. per m1, provided on both sides with a layer of cellulose acetate having 50% c0mbined acetic acid content, was superficially hydrolysed on both sides in the same way as described in Example I I, dried, washed and sensitized on one side only with a solution containing:

0.17 mol zinc chloride double salt of l-diazo-4-dicthylamino-3-chlorobenzene (type I; epsilon at 3650 A.=1.5 10 at 4050 A.=3.1 10

0.055 mol zinc chloride double salt of l-diazo-4'monocyclohexylamino-3-chlorobenzene (type 1!; epsilon at 3650 A.=3.5 10 at 4050 A.=0.2 10

3 g. tartaric acid in 250 cc. ethyl alcohol and 750 cc. water and dried.

The application was made so that the sensitized surface contained: 0.46 millimol diazo compound of type l and 0.19 millimol diazo compound of type II, per 111.

The sheet was exposed under a photographic diapositive and developed by the application of a film of approximately 9 g. per m. of the developing liquid of Example 4.

A violet copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing', in a concentration equal to the total diazo content of 1 the example, only the softer working of the diazo compounds.

Example 15 A sheet of paper of 80 g. per m3, suitable for the diazotype process, was coated with a solution, which contained:

by weight of methyl in 1 litre of water and dried.

The application was so made that the treated paper surface contained: approximately 0.5 millimol diazo compound of type I and approximately 0.2 millimol diazo compound of type II per mi.

The sheet was exposed as in Example 2 and developed as in Example 3. A dark brown copy was obtained having softer gradation than would have been obtained, under otherwise comparable circumstances, with a diazotype paper containing, in a concentration equal to the total diazo content of the example, only the more soft-working of the two diazo compounds. 1-diazo-4-ethylethanolamino-3-chlorobenzene was prepared in the same manner as the diazo compounds of Example 1, using N-ethyl-N- ethanolamine.

We claim:

1. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive diazo compound, hereinafter referred to as the type I compound, of the formula wherein R1 and R2 each represent an alkyl radical, X is an anion and Y a substituent replacing hydrogen, and at least one other light sensitive para amino benzene diazo compound, hereinafter referred to as the type II compound, said type I compound having for rays of 4050 A. an epsilon value greater than l.5 and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays of 3650 A. an epsilon value greater than x10 and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A. exceeding that of said type 11 compound for rays of 4050 A. by at least 1.0)(10, the epsilon value of said type II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least 1.O 10 the relative quantities of said type I compound and said type II compound being such that the gamma value of said diazotype material containing said mixture of diazo compounds is less than the gamma values of comparable diazotype materials respectively containing only said type I compound and only said type II compound as the lightsensitive constituent, said diazo compounds coupling more rapidly than para-diazo-diethylaniline and being incapable of forming an azo dyestufl with their own light decomposition products, the azo dyestuffs formed in the image parts of said material upon the development of such parts with a liquid containing at least one azo coupling 14 component, after an image-wise exposure of said material under polychromatic actinic light, being all of substantially the same color and being incapable of forming an azo dyestuff with their own light decomposition products.

2. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive diazo compound, hereinafter referred to as the type I compound, of the formula wherein R1 and R: each represent an alkyl radical, X is an anion and Y a substituent replacing hydrogen, and at least one other light sensitive diazo compound, hereinafter referred to as the type II compound, of the formula IIIIX HN R wherein R is an alkyl radical, X an anion and Y a substituent replacing hydrogen, said type I compound having for rays of 4050 A. an epsilon value greater than 1.5)(10 and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays of 3650 A. an epsilon value greater than 1.S 10 and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A. exceeding that of said type II compound for rays of 4050 A. by at least 1.0)(10, the epsilon value of said type II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least l.0 l0 the gamma value of said diazotype material containing said mixture of diazo compounds being less than the gamma value of comparable diazotype materials respectively containing only said type I compound and only said type II compound as the light-sensitive constituent, said diazo compounds coupling more rapidly than para-diazodiethylaniline.

3. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive diazo compound, hereinafter referred to as the type I compound, of the formula wherein R1 and R2 each represent an alkyl radical, X is an anion and Y a substituent replacing hydrogen, and at least one other light sensitive diazo compound hereinafter referred to as the type II compound, of the formula NsX wherein R is a cyclohexyl radical and X is an anion, said type I compound having for rays of 4050 A. an epsilon value greater than 1.5)(10 and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays of 3650 A. an epsilon value greater than 1.5 x10 and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A exceeding that of said type II compound for rays of 4050 A. by at least 1.0 l the epsilon value of said tvpe II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least l.0 l0 the gamma value of said diazotype material containing said mixture of diazo compounds being less than the gamma values of comparable diazotype materials respectively containing only said type I compound and only said type II compound as the lightsensitive constituent, said diazo compounds coupling more rapidly than para-diazo-diethylaniline.

4. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive diazo compound, hereinafter referred to as the type I compound, of the formula (C: l): wherein X is an anion, and at least one other light sensitive diazo compound, hereinafter referred to as the type II compound, of the formula wherein R is a cyclohexyl radical and X is an anion, said type I compound having for rays of 4050 A. an epsilon value greater than 1.5)( and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays 3650 A. an epsilon value greater than 1.5 l0* and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A. exceeding that of said type 11 compound for rays of 4050 A. by at least l.0 10 the epsilon value of said type II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least 1.0)(10, the gamma value of said diazotype material containing ill 16 said mixture of diazo compounds being less than the gamma values of comparable diazotype materials respectively containing only said type I compound and only said type II compound as the light-sensitive constituent, said diazo compounds coupling more rapidly than paradiazo-diethylaniline.

5. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive l-diazo, 3-chloro, 4-diethyl amino benzene, hereinafter referred to as the type I compound, and at least l-diazo, 3-chloro, 4-cyclohexyl-amino benzene, hereinafter referred to as the type II compound, said type I compound having for rays of 4050 A. an epsilon value greater than 1.5)(10 and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays of 3650 A. an epsilon value greater than 1.5)(10 and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A. exceeding that of said type II compound for rays of 4050 A. by at least 1.0 l0 the epsilon value of said type II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least 1.0 10 the gamma value of said diazotype material containing said mixture of diazo compounds being less than the gamma values of comparable diazotype materials respectively containing only said type I compound and only said type 11 compound as the light-sensitive constituent, said diazo compounds coupling more rapidly than para-diazo-diethylaniline.

6. A one component positive diazotype material suitable for development by the semi-wet development process, comprising a sensitized sheet material containing per square meter at least 0.3 millimol of a mixture of light sensitive diazo compounds including at least one light sensitive l-diazo, 3-chloro, 4-diethyl amino benzene, hereinafter referred to as the type I compound, and at least one I-diazo, 3-chloro, 4-(methylcyclohexyl) amino benzene, hereinafter referred to as the type II compound, said type I compound having for rays of 4050 A. an epsilon value greater than 1.5)(10 and for rays of 3650 A. an epsilon value lower than for rays of 4050 A., said type II compound having for rays of 3650 A. an epsilon value greater than 1.5 X 10 and for rays of 4050 A. an epsilon value lower than for rays of 3650 A., the epsilon value of said type I compound for rays of 4050 A. exceeding that of said type II compound for rays of 4050 A. by at least 1.0x 10 the epsilon value of said type II compound for rays of 3650 A. exceeding that of said type I compound for rays of 3650 A. by at least l.0 10 the gamma value of said diazotype material containing said mixture of diazo compounds being less than the gamma values of comparable diazotypc materials respectively containing only said type I compound and only said type II compound as the light-sensitive constituent, said diazo compounds coupling more rapidly than para-diazo-diethylaniline.

References Cited in the file of this patent UNITED STATES PATENTS 1,967,371 Schmidt et al. July 24, 1934 2,532,126 Slifkin et a1. Nov. 28, 1950 2,659,672 Leuch Nov. 17, 1953 FOREIGN PATENTS 677,772 Great Britain Aug. 20, 1952 

1. A ONE COMPONENT POSITIVE DIAZOTYPE MATERIAL SUITABLE FOR DEVELOPMENT BY THE SEMI-WET DEVELOPMENT PROCESS, COMPRISING A SENSITIZED SHEET MATERIAL CONTAINING PER SQUARE METER AT LEAST 0.3 MILLIMOL OF A MIXTURE OF LIGHT SENSITIVE DIAZO COMPOUNDS INCLUDING AT LEAST ONE LIGHT SENSITIVE DIAZO COMPOUND, HEREINAFTER REFERRED TO AS THE TYPE 1 COMPOUND, OF THE FORMULA 